Hong Kong's air pollution caused more than 1,600 premature deaths in the first half of the year, almost 40 times the number of fatalities attributed to the H7N9 avian flu virus, according to a study by the Clean Air Network.

The pollution also cost 18.7 billion Hong Kong dollars ($2.4 billion) in the six months ended June 30, said the study, citing the Hedley Environmental Index. It was responsible for 76,361 days in the hospital and 3.6 million doctor visits, it said.

All pollutants measured by the Environmental Protection Department at all of Hong Kong's 14 monitoring stations exceeded the World Health Organization's annual average air quality guidelines, with the exception of nitrogen dioxide levels at Tap Mun, the report found. The average levels of nitrogen dioxide, suspended particulates and sulfur dioxide were higher in the first half of 2013 from a year earlier, the study shows.

"This midyear air quality review shows just how critical it is that the government take immediate action to implement effective policies in order to safeguard public health," Kwong Sum-yin, chief executive officer of Clean Air Network, said in a statement Saturday. He pointed to what he said was a lack of progress in government initiatives to retire old diesel commercial vehicles, the development of optimized traffic policies and feedback on a petition to install onshore power facilities to curb emissions from ships.